Rendering SketchUp models with Kerkythea

Quickly creating 3D-models and doing sketchy renderings is clearly the strength of Google SketchUp. The full modeling feature set is even available in the free version and with downloadable Ruby plugins, anything is possible.

One feature that is missing in SketchUp, though, is photo-realistic rendering. But don't let that stop you... You can add high-quality rendering to the free SketchUp software even if you don't have any of the full-featured commercial rendering programs like 3ds max, VIZ, VRay, maxwell etc. Although there are some commercial rendering solutions available for SketchUp (namely VRay for SketchUp or Podium), I suggest you take a look at the freeware Kerkythea. For completeness, it should be mentioned that there are also the free renderers (with export plugins) Indigo and POVRAY, but I (currently) prefer Kerkythea due to its great user interface, fast and great results as well as multiprocessor support.

Kerkythea installs as a separate program and SketchUp models are converted to its XML-based scene description language with a very seamless exporter plug-in (a Ruby-plugin). The rendering engine then provides various rendering methods such as ray tracing, photon mapping, path tracing, BiPT, MLT and also presets for clay and ambient occlusion renderings. It includes a full-featured material editor and additional high-quality materials can be downloaded from the web.

This is a sample image of a SketchUp model rendered in Kerkythea (two light emitting planes, MLT render):

Installation

Download the Kerkythea installer here.
Download the SketchUp exporter plugin and the SketchUp light components here.
Optional: Download Kerkythea sample materials and models (trees etc.) here.
Install Kerkythea.
Close SketchUp. Then install the SketchUp exporter by putting the files into the SketchUp plugin folder (usually C:\Program Files\Google\Google SketchUp 6\Plugins)
Install the light components into SketchUp's component folder (usually C:\Program Files\Google\Google SketchUp 6\Components)
Optional: Start Kerkythea and under the File menu, select "Install Library..." to install the material libraries.

Use

The SketchUp exporter download includes a sample file that is very illustrative. It will guide you through scene setup, light creation, modification, animation setup, export and rendering. Go through it and you'll be up to speed very fast. More tutorials are available here and in their wiki. A very basic workflow goes like this:

Create your SketchUp model. Apply materials and position textures. Textures will be exported and you can refine these materials in Kerkythea's material editor.
Turn shadows on if you like and/or add Kerkythea light components.
Create animation (formerly tourguide) tabs/views. On export, these will be used to create cameras.
Go to the plugins menu and export the scene. This will create an XML-file and a sub-folder with all the textures. The exporter gives you options to export the selected object only, export the lights or export for a clay render (no textures). Choose as you please.
You can then directly open the model in Kerkythea by clicking OK one more time. If that doesn't work, revisit the plugin installer documentation. In any case you will be able to open Kerkythea and load the file.
Select a render preset and watch the magic happen. Start with a quick "Photon Map - Quick" preview and work your way up. Also start with a smaller size (800x600 or less). If you have multiple processors in your machine, make sure you use them all as this will speed up rendering.

These are some rendering types that can be done with this software:

Global Illumination:

I used quite "bland" materials here to speed up rendering time. You can set reflectivity or bump in Kerkythea's material editor.

Global Illumination Rendering

Ambient Occlusion:

Set the sky color to white or grey, disable the sun and see what happens. Always looks nice.

Ambient Occlusion Rendering

Image-based lighting (HDRI):

Load a spherical HDR image as a sky image in Kerkythea and you'll get very realistic lighting conditions.

For far more impressive renderings, check out their gallery.

Tips & Tricks

There are two issues with the exporter (SU2KT) that you should be aware of (brought to my attention by "notareal"):
1. SU2KT sets sun power always to 3.0. After you have opened exported scene go to Settings > Sun and sky > Adjust Sun > Adjust Sky (use physical sky for optimal lighting)
2. SU2KT uses the so called 0.85 rule with diffuse color because before KT2007 this was needed. Now you can use any color you want, pure white as well, there is no problem in KT with this (look for automatic energy conservation in Patrick's Material Editor Guide).
"Watch your back!" - All faces in SketchUp have front and back sides. Make sure you clean these up (switch all visible sides to front) in SketchUp before you export.
SketchUp objects usually have a very low polygon count, which may lead to spheres looking a bit "edgy". To fix this, highlight the object in Kerkhythea, right click on the material/object in the list, under "Modelling" click on "Weld Vertices" and then let it subdivide the mesh ("Loop Subdivision") for you.
Objects are exported from SketchUp "By Material". I.e. separate objects in SketchUp by assigning different materials to them. These can simply be different colors, of course.
As with any renderer, a large number of reflective and refractive materials (glass, metal, etc.) significantly increase rendering time. Sometimes it may be enough to just use one of SketchUp's "corrugated metal" textures and rather postprocess the image in Photoshop. Also, depth of field increases rendering time significantly. If you need to have blurred backgrounds, render a depth map in Kerkythea (one of the last settings) and add DOF in Photoshop.
Keep light emitting objects simple (i.e. use rectangles only). The higher polygon count of more complex objects will slow down any render.
One great tip for Kerkythea materials that I found on the forums: To create a good-looking material, apply one of the basic plastic materials (with the desired reflectivity) and then apply your texture to the diffuse channel.

Posted: April 19th, 2007 under AEC CAD.
Digg This! | Comments: 24 | Comments RSS

Comments

Comment from PIERRE VIDAL |
Time: May 27, 2007, 14:50

HELLO:
SEND ME PLEASE YOUR TUTORIAL IN SPANISH VERSION

THANKS

Comment from raduke |
Time: June 1, 2007, 13:01

Hi, What do you mean by ’switching all visible faces to front’? How do you do that in Sketchup. Thanx.

Comment from Alex |
Time: June 1, 2007, 13:25

@Pierre: You should voice this request on the Kerkythea forum

@ raduke: Faces in SketchUp have a front and a back. The front is light colored, the back is dark. Switch your model to monochrome view mode and see that all faces that you see are light colored).

Comment from RemR |
Time: September 18, 2007, 21:55

wooorales excelente plugins para mi SketchUp

Comment from FRANK |
Time: October 8, 2007, 07:40

HI! I HAVE BOTH SKETCHUP 6 AND KERKYTHEA SOFTWARE IN PC BUT I DON’T KNOW HOW TO USE IT (KERKYTHEA)… CAN YOU PLEASE SEND ME YOUR TUTORIALS AND SAMPLE WORKS DONE IN SKETCHUP 6 RENDERED IN KERKYTHEA? YOUR QUICK RESPONSE IS HIGHLY APPRECIATED. THANKS… MABUHAY!

Comment from Alex |
Time: October 8, 2007, 09:13

[quote comment="16324"]HI! I HAVE BOTH SKETCHUP 6 AND KERKYTHEA SOFTWARE IN PC BUT I DON’T KNOW HOW TO USE IT (KERKYTHEA)… CAN YOU PLEASE SEND ME YOUR TUTORIALS AND SAMPLE WORKS DONE IN SKETCHUP 6 RENDERED IN KERKYTHEA? YOUR QUICK RESPONSE IS HIGHLY APPRECIATED. THANKS… MABUHAY![/quote]
Take a look at the Kerkythea forums (see link above). There is a wealth of information there.

Comment from lesley |
Time: October 19, 2007, 18:50

Hi there-
I am new to sketchup rendering and I’ve downloaded the SU exporter plugin into the prescribed folder, however when I attempt to export as an XML-file, I don’t see the plugin….I have SU 5. Any suggestions? Thank you!

Comment from lesley |
Time: October 20, 2007, 20:03

never mind, I figured it out. Thanks for your other helpful information.

Comment from Turner |
Time: October 27, 2007, 16:17

I was wondering if you can help me! I downloaded and installed the exporter, but when I tried to export I don’t have the option to export XML in Animation, 2D or 3D. I put the exporter into the plugin folder as suggested and uninstalled and installed a couple of times and still nothing. Do you have any ideas what I could be doing wrong. Thank you!

Comment from Sherwin Primo |
Time: November 5, 2007, 10:21

when i render metal or reflective and even glaass like material, the image tends to be noisy (dots on reflective or glass surface)

Comment from Alex |
Time: November 6, 2007, 13:36

If you have any technical questions or problems with Kerkythea and/or the exporter, then take a look at the KT forum (link is above). A search there will typically come up with an answer to your issue.

Comment from olly |
Time: November 13, 2007, 02:17

hi, i’ve downloaded materials from kerkythea website, but i couldnti import it to kerkythea library because its not a zip, its just file folder. Do you have any ideas about this?
thanks.

Comment from Alex |
Time: November 13, 2007, 10:46

[quote comment="18792"]hi, i’ve downloaded materials from kerkythea website, but i couldnti import it to kerkythea library because its not a zip, its just file folder. Do you have any ideas about this?
thanks.[/quote]
Hi Olly, when you download the file, it should save it with a filename like something.mat.zip. If yours only shows the .mat extension, then you might have not changed the (awfully bad) Windows standard setting, which suppresses display of file extensions. You can change that in Explorer. You should still be able to import the material as mentioned above, though.

Comment from L_Verio |
Time: November 15, 2007, 04:36

Hi, I’m a sketchup user, tried to go on kerkythea-s website, but my browser said “forbidden site” .. tried from several other machines, all the same .. :S

Any idea ?

thanks

Comment from Alex |
Time: November 15, 2007, 10:52

[quote comment="18972"]Hi, I’m a sketchup user, tried to go on kerkythea-s website, but my browser said “forbidden site” .. tried from several other machines, all the same .. :S
Any idea ?
thanks[/quote]
Yes, quite odd, isn’t it? They must have screwed up their server settings. I’ll send an email.

Comment from L_Verio |
Time: November 19, 2007, 08:23

Now it works.. But there is no OSX release .. :(
Anybody knows the easyest solution for me ?
(not to change os :D )

Comment from Matias2112 |
Time: December 8, 2007, 17:44

[quote comment="5459"]HELLO:
SEND ME PLEASE YOUR TUTORIAL IN SPANISH VERSION

THANKS[/quote]

Yo te puedo mandar una versión traducida, mándame un email a matiasvolco@gmail.com

Comment from bill |
Time: December 18, 2007, 15:03

Hi,
A while back I had read something about testing this software on macs.
Are you still looking for ginnie pigs?

Thanks,

Comment from rabia |
Time: March 21, 2008, 09:32

ım rabia ım student a unıversıty ın turkey. ı have o home work.must use google sketchup. but ı dont know, how can ı do a animation in thıs program ,ı do everythıng but
nothıng move. teacher want make video me,ı dont know.maybe you cant understand me ,but please help

Comment from Lee |
Time: April 2, 2008, 06:10

When I import my models from sketchup to Kerkythea the material scales don’t come through correctly, is there a way to reset or change them?

Thanks
Lee

Comment from ariel |
Time: April 28, 2008, 22:57

how can i install this software?

Comment from JC |
Time: May 5, 2008, 14:47

PIERRE VIDAL ,

Don’t be so lazy man, take a f****ng dictionary and translate it.

Comment from Scott |
Time: May 9, 2008, 14:22

Hi Have the same problem as Lesley, I have no XML option when I try to export. I know the plugin is installed because its in the list of plugins in the help menu. In your section on use you say go to the plugin menu and export the file. Can you tell me where the Plugin Menu is? Do you need sketchup pro for this?

Comment from Alex |
Time: May 9, 2008, 14:33

If everything is installed correctly, then you’ll find a “Plugins” menu on the SketchUp menu bar (at least on Windows). Go to “Kerkythea Exporter > Export Model” and okay the dialog box. It will then export the model as an XML file. You are right, there is no added XML export option in SketchUp’s File dialog, you must go through the exporter plugin. Hope this helps…

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